Polymethine dyestuffs



Patented Feb. 4, 1941 UNITED STATES PATENT OFFICE POLYMETHINE DYESTUFFS aware No Drawing. Original application August 31,

1936, Serial No. 98,823.

Divided and this a1 plication November .12, 1938, Serial No. 240,052. In Germany September 7, 1935 3 Claims.

The present invention relates to dyestuffs oi the polymethine series.

We have found that new dyestuffs of the polymethine series distinguished by excellent tinctorial properties can be obtained by employing in the preparation of these dyestufis nitriles of the general formula wherein R stands for hydrogen or an alkyl, hy-

droxyalkyl or aralkyl radicle, or their substitu- 1 tion or saponification products, nitrile groups present in the resulting dyestufis being wholly or partly saponified if desired. The arylaminobeta-propionitriles serving as starting'materials according to this invention may be prepared in accordance with the U. S. Patent No. 1,992,615 by adding primary or. secondary aromatic amines to acrylic acid nitrile.

The dyestuffs may be prepared according to this invention for example by condensing the above mentioned nitriles or substitution or saponification products thereof with methyleneindoline-omega aldehydes or by condensing the said compounds which contain an aldehyde group attached to an aryl radicle with any compound 30 containing reactive methylene groups. The resulting dyestuffs are distinguished by a. good clarity and iastness of the dyeings. Their shade of color is considerably displaced towards red as compared with the corresponding dyestuffs without the propionitrile group.

According to our invention both water soluble and water insoluble dyestuffs may be obtained. Generally speaking the polymethine dyestufis derived from an indoline are water soluble and 40 most suitable for dyeing cotton mordanted with tannin or acetate artificial silk. When employing compounds containing reactive methylene groups such as cyanacetic acid esters or arylides, malonic acid .dinitrile or aceto acetic acid arylides 5 the resulting dyestufis are water-insoluble and most suitable for dyeing acetate artificial silk.

The following examples will further illustrate how the said invention may be carried out in practice but the invention is not restricted to 50 these examples. The parts are by weight.

Example 1 80 parts of 1,3,3-trimethyl-2-methyleneindoline-omega-aldehyde and '72 parts of N-ethyl-N- 55 phenyl-beta-amino-propionitri1e are dissolved in 90 parts of benzene. 63 parts of phosphorus oxychloride are allowed to flow in slowly at 20 C. while cooling. The mixture is heated to boiling for about an hour on a steam bath, introduced into 2000 parts of water and the benzene distilled 5 off. The resulting dyestuff is deposited by the addition of common salt, separated from the acid liquid and obtained in the form of dark violet lustrous prisms by crystallization from hot water and filtration of the solution from resinous by-products. The product dyes cotton mordanted with tannin clear red shades. It corresponds to the formula C Ha 02in By sapom'iying the nitrile group by means of strong mineral acids, a dyestuif is obtained which dyes cotton mordanted with tannin more bluish shades. 5

Example 2 CHZCHPCN by-products. The resulting dyestufi dyes cotton mordanted with tannin clear bluish red shades. 40 It corresponds to the formula c1130 CH3 -CHa 0%: \c1 CH2CH2-CN The same dyestufi" is also obtained by condensing the N methyl-N-beta-propionitrile paraaminobenzaldehyde having a boiling point of from 220 to 222 C. at a pressure of 3 millimeters (mercury gauge) (obtainable from N-methyl-N- phenyl-beta-amino-propionitrile by treatment With methyl-formanilide and phosphorus oxychloride) (see Berichte .der Deutschen Chemischen Gesellschaft 60, page 119) with 5-methoxy- 1.3.3-trimethyl-Z-methyleneindoline by means of glacial acetic acid.

Example 3 231 parts of 5-methoxy-1,3,3-trimethyl-2- methylene-indoline-omega-aldehyde and 23.6 parts of N-benzyl-N-phenyl-beta-aminopropionitrile are dissolved in parts of benzene and condensed with 15.5 parts of phosphorus oxychloride in the manner described in Example 2. A dyestuff is obtained which dyes cotton mordanted with tannin bluish red shades. It corresponds to the formula 18.8 parts of N-methyl-N-beta-propionitrilepara-amino-benzaldehyde (see Example 2) and 11.3 parts of cyanoacetic acid ethyl ester are dissolved in 50 parts of ethyl alcohol; 0.5 part of piperidine is added and the whole heated to boiling for about onequarter of an hour. The solution becomes intense yellow in color. The condensation product formed crystallizes in the cold giving yellow crystals. It dyes acetate artificial silk clear green-yellow shades. The dyestuif corresponds to the formula mangle If 20.2 parts of N-ethyl-N-beta-propionitri1epara-amino-benzaldehyde (boiling point from 205 to 207 C. at a pressure of 1 millimeter (mercury gauge)) be employed instead of 18.8 parts of N-methyl-N-betapropionitrile-para-aminobenzaldehyde, a dyestuff is obtained which dyes acetate artificial silk more reddish shades. corresponds to the formula NC CHaOHa 02115000 CHQCHECN This application-has been divided out of application Ser. No. 98,823, filed August 31, 1936.

What we claim is: 1. Polymethine dyestuffs corresponding to the general formula CHzCHzY GEN wherein R1 stands for an alkyl radicle, R stands for a member of the group consisting of hydrogen, alkyl and benzyl, and wherein Y stands for a member of the group consisting of GEN and its saponification products.

3. Polymethine dyestuffs corresponding to the general formula GEN - CzH5OOC CHnCHzY wherein Y stands for a member of the group consisting of CEN and its saponification products.

' CARL WINTER.

NIKOLAUS RO-H.

CHzCHzY 

